Enhancing ESL Learners' Experience and Performance through Gradual Adjustment of Video Speed during Extensive Viewing

Adjusting video playback speed during extensive viewing is crucial for English-as-a-Second-Language (ESL) learners to enhance their learning experience. Since existing research suggests that abrupt speed changes might negatively impact the viewing experience, several novel speed-adjustment systems have been proposed to provide adaptive and optimal video playback speed for learners. However, empirical evidence is still sparse on whether gradual adjustments truly offer a superior experience compared to immediate changes. To delve into this, we conducted a study with 32 ESL participants, comparing direct and gradual adjustments on flow state, cognitive load, and behavioral measures. Employing both objective metrics, such as pupil diameter, and subjective feedback from surveys, our results strongly favor the gradual method. It not only enhanced flow state and video comprehension but was also less obtrusive to learners. These findings underscore the advantages of gradual speed adjustment for ESL learners, offering insights for the design of next-generation speed-adjustment systems.